The solenoid of the camshaft adjuster is sealed from the factory by nothing more than a plain sealing ring, and over time that starts to leak.
Applies to the engine M276DE30AL, M276DES35, M271DE18AL.
Repair: from 31 EUR
vinkodex.Mercedes-Benz SLC-Class R172 common faults.
2016–2021. The fault list covers this generation and the engines in it. If the listing gives the exact version, pick it below.
Markus Jordan / CC BY-SA 3.0
What to watch for
What can go wrong on this car?
The list covers the generation, the engines and the transmissions. Once you pick the version, only the faults that apply to it stay.
critical5
On engines built between July and September 2015 the supplier made a mistake in the welding process, so the weld seam on the camshaft is not as it should be.
Applies to the engine M274DE16AL, M274DE20AL.
On the four cylinder, supercharged 1.8 M271 the timing chain stretches and the sprockets of the camshaft adjuster (Nockenwellenversteller) wear out.
Applies to the engine M271DE18AL.
The chain tensioner seal starts to leak and engine oil can drip onto the exhaust system.
Applies to the engine OM651DE22LA.
The sealing ring of the chain tensioner starts to let through, and engine oil escapes at the tensioner.
Applies to the engine OM651DE22LA.
expensive3
On the 2.0 turbo four cylinder (M274, and the transverse M270) the control valve of the crankcase ventilation system fails early.
Applies to the engine M274DE16AL, M274DE20AL.
At a cold start a brief, metallic rattle comes from the front of the engine, and it has two causes.
Applies to the engine M276DE30AL, M276DES35.
In the Mercedes 7 speed 722.9 automatic (7G-Tronic / 7G-Tronic Plus) the mechatronics unit and the conductor plate (Leiterplatte) age over time: jerking on shifts, delayed engagement, a "Getriebe schützen" message, and fault codes on the gearbox electronics.
Applies to the transmission MB7229.
3 more faults belong to this generation. On the version page, only the ones that apply stay.
Engines and transmissions in this generation
A fault is often tied to the engine, not to the whole generation. You find the engine code in the registration document.
R172 · 2016–2021
Pick the version.
The fault list opens on the version page.
4 versions
EngineVersionPowerFuel · transmissionBody
1.6 l · 1595 cm³
M274DE16AL · MB7250
SLC 180
2016–2021 · SLC 180
156 HPpetrol · automaticconvertible1.6 l · 1595 cm³
M274DE16AL · MB6MT
SLC 180
2016–2021 · SLC 180
156 HPpetrol · manualconvertible2.0 l · 1991 cm³
M274DE20AL · MB7250
SLC 200
2016–2021 · SLC 200
184 HPpetrol · automaticconvertible3.0 l · 2996 cm³
M276DE30AL · MB7250
SLC 43 AMG
2016–2021 · SLC 43 AMG
367 HPpetrol · automaticconvertible
Neighbouring generations
R172 · 2016–2021
R172 (2016-2021). If the listing is from the changeover year, look at the neighbour too.
Previous generation
This is the earliest.
This generation
R172 · 2016–2021
Next generation
This is the latest.
Common questions
About this generation
Which years does this page cover?
2016–2021. The changeover year can fall in two generations. If the listing is from that year, look at the neighbour too.
Does the fault apply to every car like this?
No. It depends on the engine and the transmission too.
Is it free?
The fault list is.
Information, not an expert opinion
We write the descriptions, and we put the source next to them. A person reviews them before they go out. They are still information, not a technical expert opinion.
- A fault on the list does not mean the car you are looking at has it.
- A fault missing from the list does not mean the model is fault-free. Write-ups are made model by model. Not all of them are done.
- You decide whether to buy. This is no substitute for an inspection. That needs a workshop and a history check.